Examining the traits of overweight and obese adults

Study of the Phenotype of Overweight and Obese Adults

Observational National Institutes of Health Clinical Center (CC) · NCT00428987

This study looks at the physical and lifestyle traits of overweight and obese adults to see what factors might make it hard for them to lose weight and keep it off.

Quick facts

Study typeObservational
Enrollment2000 (estimated)
Ages18 Years to 100 Years
SexAll
SponsorNational Institutes of Health Clinical Center (CC) NIH
Locations1 site (Bethesda, Maryland)
Trial IDNCT00428987 on ClinicalTrials.gov

What this trial studies

This observational study aims to characterize the physical and behavioral traits of overweight and obese individuals, including their hormones, metabolism, food preferences, fitness levels, sleep patterns, and cognitive processes. Participants over 18 years old, from various weight categories, will undergo a series of tests such as metabolic studies, resting metabolic rate assessments, and glucose tolerance tests. The study will also collect genetic material to explore the internal factors influencing body weight. By understanding these traits, the research seeks to identify barriers to weight loss and weight regain.

Who should consider this trial

Good fit: Ideal candidates include adults over 18 years old who are classified as obese (BMI > 30), overweight (BMI 25-30), or normal weight (BMI 18.5-25).

Not a fit: Patients with significant physical limitations or unstable medical conditions may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to more personalized and effective weight management strategies for individuals struggling with obesity.

How similar studies have performed: Other studies have shown success in characterizing obesity-related traits, but this study's comprehensive approach to phenotype analysis is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
* INCLUSION CRITERIA:

Obese subjects:

1. Obese men and women over the age of 18 years
2. BMI \> 30

Overweight subjects:

1. Overweight men and women over the age of 18 years
2. BMI \> 25 and \< 30

Control subjects (may be matched for age, sex and years of education):

1. Normal weight men and women over the age of 18 years
2. BMI \> 18.5 and \< 25

EXCLUSION CRITERIA:

1. Patients with significant physical limitations that may preclude them from completing the majority of the tests in this study
2. Current unstable medical conditions including cardiac ischemia, severe respiratory insufficiency requiring oxygen therapy, hepatic or cardiac failure as assessed by history and physical exam
3. Any psychiatric condition that would preclude participation in the study
4. Patients unwilling or unable to give informed consent
5. Pregnant woman.

Additional exclusion for lean control subjects:

1. Previous history of obesity as an adolescent or adult
2. Current or past history of eating disorders such as anorexia nervosa or bulimia

The NIH Patient Recruitment and Public Liaison Office will receive inquiries from interested study subjects. Pre-screening by this office will exclude patients who require more than minimal assistance to complete activities of daily living in order to select subjects who can safely participate in the full phenotyping protocol. All others will be contacted by the protocol team to review exclusion criteria. Eligible patients will be invited to Clinical Research Center for a screening visit.

Where this trial is running

Bethesda, Maryland

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions ObesityHealthy VolunteersEnergy ExpenditureBody CompositionMetabolismPhenotypeNatural HistoryMorbid Obesity
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.